Is there any scaling method to resize with samplin

BlitzMax Forums/BlitzMax Programming/Is there any scaling method to resize with samplin

D4NM4N

(Posted 2009) [#1]

Is there any scaling method in MAX to resize an image with inteligent re-sampling? I need to make some (quality) thumbnails from like 3000 images.

Speed not an issue as its a batch-render process, not a game.

Arowx

(Posted 2009) [#2]

I think there is only MIPMAPPED (flag, Used when loading an image), you could always scale buy averaging the pixel values using a TPixmap which gives you acces to individual pixels in an image.

Other than could you specify what kind of re-sampling your after?

ImaginaryHuman

(Posted 2009) [#3]

Either use FILTEREDIMAGE with images, draw it scaled down to the backbuffer and grab it, or write your own floating-point bilinear filter using pixamps.

D4NM4N

(Posted 2009) [#4]

Ok thx.

I want the kind of scaling that doesnt simply do a linear chop. What i am after is the kind of photoshop/gimp/paintshop resize (bilenear i think) that can preserve/antialias the strong details (like scaling a lineart drawing).

I will try the regrabbing a draw with filteredimage flag and see what that gets me.

Failing that i guess i will have to write my own (groan)

Jesse

(Posted 2009) [#5]

but don't you need the alpah channel? if you grab from the backbuffer you loose the alpha channel.

D4NM4N

(Posted 2009) [#6]

Not for this no.

Brucey

(Posted 2009) [#7]

What about one of those Windows batch image manipulation apps?

Otus	(Posted 2009) [#8]

I had to do the same a few months back for some hundreds of images. I used Brucey's FreeImage Wrapper. Here's my code (quick & dirty), in case you find something in it useful:

SuperStrict

Framework brl.standardio

Import brl.system
Import bah.freeimage

Local size:Int = 425

Local src:String = RequestDir("Source dir...")

If Not FileType(src) Then End

Local tgt:String = RequestDir("Target dir...")

If FileType(tgt) <> FILETYPE_DIR Then End

Local dir:Int = ReadDir(src)

src = StripSlash(src)+"/"
tgt = StripSlash(tgt)+"/"

Repeat 
	Local f:String = NextFile(dir)
	Select f
	Case ""
		Exit
	Case ".", ".."
		Continue
	Default
		Print f+"..."
		Local p:TFreeImage = Null
		While Not p
			p = LoadFreeImage(src+f)
		Wend
		Local w:Int = p.width
		Local h:Int = p.height
		Print "Old size: "+w+"x"+h
		If w>h
			h :* Double(size)/w
			w = size
		Else
			w :* Double(size)/h
			h = size
		End If
		Print "New size: "+w+"x"+h
		Local p2:TFreeImage = p.rescale( w, h, FILTER_LANCZOS3 )
		f = StripExt(f)+".jpg"
		If p2.save( tgt+f, FIF_JPEG, JPEG_QUALITYSUPERB | JPEG_PROGRESSIVE )
			Print "Done."
		Else
			Print "Error: "+tgt+f
		End If
		GCCollect
	End Select
Forever

Print "All done."

D4NM4N

(Posted 2009) [#9]

hmm, thanks for that i will analyse it now :)